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Environment drives the co-occurrence of bacteria and microeukaryotes in a typical subtropical bay

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Journal of Oceanology and Limnology 2023年第6期41卷 2292-2308页

作者： Yifan MA Lingfeng HUANG Wenjing Zhang State Key Laboratory of Marine Environmental Science Marine Biodiversity and Global Change Research CenterCollege of Ocean and Earth SciencesXiamen UniversityXiamen 361102China Xiamen Key Laboratory of Urban Sea Ecological Conservation and Restoration Xiamen UniversityXiamen 361102China Fujian Key Laboratory of Coastal Pollution Prevention and Control Xiamen UniversityXiamen 361102China Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems College of the Environment and EcologyXiamen UniversityXiamen 361102China

The co-occurrence of bacteria and microeukaryote species is a ubiquitous ecological phenomenon,but there is limited cross-domain research in aquatic environments.We conducted a network statistical analysis and visualization of microbial cross-domain co-occurrence patterns based on DNA sampling of a typical subtropical bay during four seasons,using high-throughput sequencing of both 18S rRNA and 16S rRNA genes.First,we found obvious relationships between network stability and network complexity indices.For example,increased cooperation and modularity were found to weaken the stability of cross-domain networks.Secondly,we found that bacterial operational taxonomic units(OTUs)were the most important contributors to network complexity and stability as they occupied more nodes,constituted more keystone OTUs,built more connections,more importantly,ignoring bacteria led to greater variation in network robustness.Gammaproteobacteria,Alphaproteobacteria,Bacteroidetes,and Actinobacteria were the most ecologically important groups.Finally,we found that the environmental drivers most associated with cross-domain networks varied across seasons(in detail,the network in January was primarily constrained by temperature and salinity,the network in April was primarily constrained by depth and temperature,the network in July was mainly affected by depth,temperature,and salinity,depth was the most important factor affecting the network in October)and that environmental influence was stronger on bacteria than on microeukaryotes.

关键词： co-occurrence network cross-domain network stability network complexity subtropical bay

Decadal variation and trend of the upper layer salinity in the South China Sea from 1960 to 2010

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Journal of Oceanology and Limnology 2022年第4期40卷 1333-1348页

作者： Wenjing Zhang Weiqiang WANG Huibin XING State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China University of Chinese Academy of Sciences Beijing 100049China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou 511458China South China Sea Information Center State Oceanic AdministrationGuangzhou 510301China South China Sea Marine Prediction Center State Oceanic AdministrationGuangzhou 510310China

Ocean salinity is an essential measurable indicator of water cycle and plays a crucial role in regulating ocean and climate change.Using Simple Ocean Data Assimilation(SODA)reanalysis product,substantial decadal variability of the salinity in the upper layer of the South China Sea(SCS)from 1960 to 2010 was examined.Results show that a decadal variation of the upper layer salinity is clear.The upper layer(100 m)waters are found to freshen from 1960,become saltier during 1975 to 1995,and freshen again from 1995 to 2010.The strongest anomalies appear in the northeastern,northern,and northwestern regions in the three periods,respectively.The salinity variation trends become weaker below the upper layer,except the salinifi cation trend in the northern SCS extends to at least 300 m during the salinifi cation period.Diagnosis of the salinity budget over the top 100 m shows that during the fi rst freshening period horizontal advection,vertical advection,and surface freshwater forcing all contribute to salinity freshening,and horizontal advection is relatively larger.The contribution of horizontal advection and surface freshwater forcing to the positive salinity anomaly is comparable,while the vertical advection is the secondary factor in the salinifi cation period.Horizontal advection,especially zonal advection,plays a crucial role during the second freshening period.Moreover,horizontal advection is more important than that in the fi rst freshening period.In addition,the contribution of horizontal advection is mainly in zonal direction controlled by Kuroshio intrusion.Further analysis shows the upper-layer salinity variations have a Pacifi c Decadal Oscillation(PDO)-like signal,with freshening during the negative PDO years,and salinifi cation during the positive PDO years.PDO mainly infl uences the upper-layer salinity changes through both atmospheric bridge and oceanic bridge.

关键词： salinity South China Sea(SCS) decadal variation trend salinity budget analysis

Mobile Jammer-Aided Secure UAV Communications via Trajectory Design and Power Control

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China Communications 2018年第8期15卷 141-151页

作者： An Li Wenjing Zhang Department of Electronic Information Engineering Nanchang University

To further promote the achievable average secrecy rate for UAV-ground communications, a UAV-aided mobile jamming strategy was proposed in this paper. Specifically, an additional cooperative UAV is employed as a mobile jammer to transmit the jamming signal to help keep the source UAV closer to the ground destination, thus establishing more favorable legitimate link and enhancing the secrecy performance. We aimed to maximize the achievable secrecy rate by jointly optimizing the trajectories and transmit power of both source UAV and jammer UAV. To solve the considered non-convex optimization problem, we presented a block coordinate descent based iterative algorithm to address a sequence of approximated convex problems for the optimized parameter block by block to find a local optimal solution. Numerical results verify that the proposed algorithm can achieve significant secrecy rate gain compared to all the benchmark schemes.

关键词：轨道设计 UAV 通讯 jammer 安全拥挤控制联合优化

Homogeneous selection is not always important in bacterial community in the eutrophic enclosed bay

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Ecological Processes 2022年第1期11卷 363-373页

作者： Junwei Zhu Yifan Ma Lingfeng Huang Wenjing Zhang State Key Laboratory of Marine Environmental Science Marine Biodiversity and Global Change Research CenterCollege of Ocean and Earth SciencesXiamen UniversityXiamenChina Xiamen Key Laboratory of Urban Sea Ecological Conservation and Restoration Xiamen UniversityXiamenChina Fujian Key Laboratory of Coastal Pollution Prevention and Control Xiamen UniversityXiamenChina Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems College of the Environment and EcologyXiamen UniversityXiamenChina

Background:Previous studies have found that coastal eutrophication increases the influence of homogeneous selection on bacterial community assembly.However,whether seasonal changes affect the dominance of homogenous selection in bacterial community assembly in eutrophic bays remains unclear.Sansha Bay is an enclosed bay with ongoing eutrophication,located in the southeast coast of China.We investigated the bacterial community composition at two depths of the enclosed bay across seasons and the seasonal variation in community assembly processes.Results:Diversity analyses revealed that the bacterial community composition among seasons differed significantly.By contrast,there was little difference in the community composition between the two depths.The temperature was the key environmental factor influencing the community composition.The null model indicated that the relative importance of homogeneous selection decreased in the following order:spring>winter>autumn>summer.Homogeneous selection did not always dominate the community assembly among seasons in the eutrophic bay.The effects of pure spatial variables on the community assembly were prominent in autumn and winter.Conclusions:Our results showed the seasonal influence of eutrophication on bacterial community diversity.The seasonal variation in composition and structure of bacterial communities eclipsed the vertical variability.Eutrophication could enhance the importance of homogeneous selection in the assembly processes,but the seasonal environmental differences interfered with the steady-state maintained by ongoing eutrophication and changed the community assembly processes.Homogeneous selection was not always important in bacterial community in the eutrophic enclosed bay.The bacterial community was the most complex in summer,because the composition differed from other seasons,and the assembly process was the most intricate.These findings have contributed to understanding bacterial community composition and assembly processes in eutrophic coastal ecosystems.

关键词： Homogeneous selection Subtropical enclosed bay Assembly processes Bacteria community

Bandgap engineering of high mobility two-dimensional semiconductors toward optoelectronic devices

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Journal of Materiomics 2023年第3期9卷 527-540页

作者： Qiaoyan Hao Peng Li Jidong Liu Jiarui Huang Wenjing Zhang International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education Institute of Microscale OptoelectronicsShenzhen UniversityShenzhen518060China Shenzhen Institute of Advanced Electronic Materials Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen518103China

Over the last few years,great advances have been achieved in exploration of high-mobility two-dimensional(2D)semiconductors such as metal chalcogenide InSe and noble-transition-metal dichal-cogenide PdSe_(2).These materials are competitive candidates for constructing next-generation optoelec-tronic devices owing to their unique crystalline and electronic structures.Moreover,the optical and electronic properties of 2D materials can be efficiently modified via precisely engineering their band structures,which is critical for widening specific applications ranging from high-performance opto-electronics to catalysis and energy harvesting.In this review,we focus on the progress in bandgaps engineering of newly emerging high-mobility 2D semiconductors and their applications in optoelec-tronic devices,incorporating our recent study in the InSe and PdSe_(2)systems.First of all,we discuss the structure-property relationship of typical high-mobility 2D semiconductors(InSe and PdSe 2).Next,we analyze several viable strategies for bandgap engineering,including thickness,strain or pressure,alloying,heterostructure,surface modification,intercalation,and so on.Furthermore,we summarize the optoelectronic devices fabricated with such high-mobility 2D semiconductors.The conclusion and outlook in this topic are finally presented.This review aims to provide valuable insights in bandgap engineering of newly emerging 2D semiconductors and explore their potential in future optoelectronic applications.

关键词： High mobility 2D semiconductors Bandgap engineering Alloying Heterostructure

Applicability evaluation of ERA5 wind and wave reanalysis data in the South China Sea

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Journal of Oceanology and Limnology 2023年第2期41卷 495-517页

作者： Rongwei ZHAI Caijing HUANG Wei YANG Ling TANG Wenjing Zhang South China Sea Information Center of State Oceanic Administration Guangzhou 510310China Key Laboratory of Marine Environmental Survey Technology and Application Ministry of Natural ResourcesGuangzhou 510300China South China Sea Marine Surveying and Technology Center State Ocean AdministrationGuangzhou 510300China

Wind and wave data are essential in climatological and engineering design applications.In this study,data from 15 buoys located throughout the South China Sea(SCS)were used to evaluate the ERA5 wind and wave data.Applicability assessment are beneficial for gaining insight into the reliability of the ERA5 data in the SCS.The bias range between the ERA5 and observed wind-speed data was-0.78-0.99 m/s.The result indicates that,while the ERA5 wind-speed data underestimation was dominate,the overestimation of such data existed as well.Additionally,the ERA5 data underestimated annual maximum wind-speed by up to 38%,with a correlation coefficient>0.87.The bias between the ERA5 and observed significant wave height(SWH)data varied from-0.24 to 0.28 m.And the ERA5 data showed positive SWH bias,which implied a general underestimation at all locations,except those in the Beibu Gulf and centralwestern SCS,where overestimation was observed.Under extreme conditions,annual maximum SWH in the ERA5 data was underestimated by up to 30%.The correlation coefficients between the ERA5 and observed SWH data at all locations were greater than 0.92,except in the central-western SCS(0.84).The bias between the ERA5 and observed mean wave period(MWP)data varied from-0.74 to 0.57 s.The ERA5 data showed negative MWP biases implying a general overestimation at all locations,except for B1(the Beibu Gulf)and B7(the northeastern SCS),where underestimation was observed.The correlation coefficient between the ERA5 and observed MWP data in the Beibu Gulf was the smallest(0.56),and those of other locations fluctuated within a narrow range from 0.82 to 0.90.The intercomparison indicates that during the analyzed time-span,the ERA5 data generally underestimated wind-speed and SWH,but overestimated MWP.Under non-extreme conditions,the ERA5 wind-speed and SWH data can be used with confidence in most regions of the SCS,except in the central-western SCS.

关键词： ERA 5 reanalysis data wind speed significant wave height mean wave period South China Sea(SCS)

The model of tracing drift targets and its application in the South China Sea

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Acta Oceanologica Sinica 2022年第4期41卷 109-118页

作者： Yang Chen Shouxian Zhu Wenjing Zhang Zirui Zhu Muxi Bao Key Laboratory of Marine Hazards Forecasting of Ministry of Natural Resources Hohai UniversityNanjing 210098China College of Oceanography Hohai UniversityNanjing 210098China College of Meteorology and Oceanography National University of Defense TechnologyNanjing 211101China Nanjing Maritime Safety Administration Nanjing 210009China

A Leeway-Trace model was established for the traceability analysis of drifting objects at sea.The model was based on the Leeway model which is a Monte Carlo-based ensemble trajectory model,and a method of realistic traceability analysis was proposed in this study by using virtual spatiotemporal drift trajectory prediction.Here,measured data from a drifting buoy observation experiment in the northern South China Sea in April 2019,combined with surface current data obtained from the finite volume community ocean model(FVCOM),were used for the traceability analysis of humanoid buoys.The results were basically consistent with the observations,and the assimilation of measured current data can significantly improve the accuracy of the traceability analysis.Several sensitive experiments were designed to discuss the effects of wind and tide on the traceability analysis,and their results showed that the wind-driven current and the wind-induced leeway drift are both important to the traceability analysis.The effect of tidal currents on traceability could not be ignored even though they were much weaker than the residual currents in the experimental area of the northern South China Sea.

关键词： South China Sea FVCOM Leeway-Trace model traceability analysis

Subharmonic resonance of single-degree-of-freedom piecewise-smooth nonlinear oscillator

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Acta Mechanica Sinica 2020年第5期36卷 1109-1118,I0003页

作者： Jiangchuan Niu Wenjing Zhang Yongjun Shen Shaopu Yang State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China School of Mechanical Engineering Shijiazhuang Tiedao UniversityShijiazhuang 050043China

Take the single degree of freedom nonlinear oscillator with clearance under harmonic excitation as an example,the 1/3 subharmonic resonance of piecewise-smooth nonlinear oscillator is investigated.The approximate analytical solution of 1/3 subharmonic resonance of the single-degree-of-freedom piecewise-smooth nonlinear oscillator is presented.By changing the solving process of Krylov-Bogoliubov-Mitropolsky(KBM)asymptotic method for subharmonic resonance of smooth nonlinear system,the classical KBM method is extended to piecewise-smooth nonlinear system.The existence conditions of 1/3 subharmonic resonance steady-state solution are achieved,and the stability of the subharmonic resonance steady-statesolution is also analyzed.It is found that the clearance affects the amplitude-frequency response of subharmonic resonance in the form of equivalent negative stiffness.Through a demonstration example,the accuracy of approximate analytical solution is verified by numerical solution,and they have good consistency.Based on the approximate analytical solution,the infuences of clearance on the critical frequency and amplitude-frequency response of 1/3 subharmonic resonance are analyzed in detail.The analysis results show that the KBM method is an effective analytical method for solving the subharmonic resonance of piecewise-smooth nonlinear system.And it provides an effective reference for the study of subharmonicr esonance of other piecewise-smooth systems.

关键词： Subharmonic resonance Piecewise-smooth system Approximate analytical solution Asymptotic method

Observational characteristics and dynamic mechanism of low-salinity water lens for the offshore detachment of the Changjiang River diluted water in August 2006

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Acta Oceanologica Sinica 2021年第3期40卷 34-45页

作者： Zhenyu Liu Wenjing Zhang Xuejun Xiong Shouxian Zhu College of Meteorology and Oceanography National University of Defense TechnologyNanjing 211101China First Institute of Oceanography Ministry of Natural ResourcesQingdao 266061China College of Oceanography Hohai UniversityNanjing 211101China

The Changjiang River diluted water(CDW)spreads into the East China Sea(ECS)primarily in a plume pattern,although in some years,low-salinity water lenses(LSWLs)detach from the main body of the CDW.In-situ observations indicate that in August 2006,a LSWL detached from the main body of the CDW near the river mouth.In this paper,the effects of winds,tides,baroclinity and upwelling on LSWLs are explored with a threedimensional model.The results show that:(1)winds play a crucial role in these detachment events because windinduced northerly Eulerian residual currents impose an uneven force on the CDW and cut it off,thus forming a LSWL;(2)upwelling carries high-salinity water from the lower layer to the upper layer,truncating the low-salinity water tongue vertically,which is conducive to the detachment and maintenance of LSWLs;and(3)upwelling during the evolution of a LSWL is caused by the combined effects of winds and tides.The influences of windinduced upwelling are mainly near the shore,whereas the upwelling along the 30 m isobath is predominantly affected by tides,with the effect increasing from neap tide to spring tide.

关键词： Changjiang River diluted water low-salinity water lens numerical simulation observational characteristics dynamic mechanism upwelling